This is to prevent accidental destabilisation in certain cases.

So I've lost my fully built temple several times the same way, you can call me stupid or whatever, I just think that if this is now thought out as a bug maybe the fix isnt quite there yet.

"Temple Destabilisation no longer happens automatically, players must click the Close Temple button after each run. This is to prevent accidental destabilisation in certain cases."

So I run 10 temples, takes me the whole day. After a while I normally lose count if I have the temple opened from the last run or is it a newly opened one. I go visit the hideout for whatever reason and when I get back the portal is gone, only thing left to do is to click "close temple". With the fix it doesn't automatically dismantle the temple, now I get to press the button myself. I thank you for this great opportunity, art is meant to stir up some feelings and this piece of art game surely does that.

When you create a portal inside the temple and click it, the game asks "ARE YOU SURE YOU WANNA LEAVE?" if you press yes, you portal out and nothing happens to your temple, just go back in.

If you open a temple and leave the zone, there is no are you sure about anything, mostly cos you and the game know that you are not sure so its a void question to ask. just enjoy closing the temple afterwards.